Conventionally, to separate right and left visual fields of a stereoscopic image, the right and left visual fields are displayed one over the other (by projection) by right and left linear polarized lights, which are orthogonal to each other, or right and left circular polarized lights, which rotate in opposite directions, and are separately viewed using polarization eyeglasses, the right and left sides of which are orthogonal to each other, or circular polarization eyeglasses, the right and left of which rotate in opposite directions, depending on a display system, to appreciate the stereoscopic image. However, in recent years, as a writing speed of a direct view type display (particularly, an LCD (Liquid Crystal Display)) has increased, right and left images composing a stereoscopic image have been alternately displayed by time division even in a direct view type LCDTV (Liquid Crystal Display Television) or the like, and an attempt to separate right and left visual fields by visual field separating eyeglasses (e.g., liquid crystal shutter eyeglasses) to perform stereoscopic viewing has been made.
However, the liquid crystal shutter eyeglasses use two polarizing plates one over the other, and thus has the disadvantage in that transmitted light is significantly attenuated and the visual fields become dark. Moreover, the shutter eyeglasses guide a light beam (polarized light beam), which has been transmitted by the polarizing plate on their front surface in a direction orthogonal to a direction of the polarizing plate on their rear surface when the visual fields are closed, to alternately open and close the visual fields. Due to such a shutter function, an opening time becomes one-half or less and a light amount is attenuated. This shutter function intermits not only a stereoscopic image but also surrounding environmental light. Therefore, the problem that a flicker occurs under illumination, which is turned on at a commercial frequency, has been pointed out.
In the direct view type display, the right and left images are difficult to simultaneously display (however, images to be displayed by polarized lights in different directions for each line exist). Therefore, it has also been proposed that the right and left images are displayed by time division by linear polarized light in one direction and are separately viewed by devising eyeglasses on the appreciation side.
However, if the viewer tilts his/her head at his/her destiny using linear polarized light, it is difficult to avoid a program of a crosstalk (e.g., Patent literature 1).
Further, a person's eyesight (diopter) differs from individual to individual. However, there are no existing stereoscopic image appreciation eyeglasses including a diopter correction lens. Therefore, the stereoscopic image eyeglasses are overlaid on eyeglasses usually used when used in the present circumstances.